This subject matter disclosed in this specification relates to a method, and its associated system and program storage device and computer program, which is adapted to be practiced by a ‘Coarsening Software’ stored in a memory of a computer system, the method relating to optimal gridding in reservoir simulation and replacing all or parts of a fine grid with a coarser grid in reservoir simulation while preserving a simulation model output, such as the ‘cumulative oil production’.
Simulation performance is a crucial consideration in optimization problems involving reservoir simulation tools. Such simulation models often involve grids sufficiently resolved to capture the complexities in the geological structures present. This level of detail is needed so that subsequent pressure and saturation profiles may be deemed a reasonable basis from which large capital decisions may be made. The ‘cost’ of using such detailed grids includes long simulation run times. This ‘cost’ or ‘downside’ is magnified when the reservoir simulator is repeatedly called, as is the case in reservoir forecast optimization.
In this specification, a ‘Coarsening Software’, also known as a ‘coarsening algorithm’ or an ‘Optimization Algorithm’ or an ‘Optimizer’, is disclosed. This ‘Coarsening Software’ or ‘Optimizer’ was developed to establish an optimal coarse grid proxy that can replace all, or parts, of a fine grid, in reservoir simulation, with a coarser grid while preserving the accuracy of some predefined ‘simulation model outputs’, where one such ‘simulation model output’ includes a ‘cumulative field oil production’ also known as the ‘Field Oil Production Total’ or ‘FOPT’.